Co-metabolic biodegradation of 4-bromophenol in mixture of pollutants system by Arthrobacter chlorophenolicus A6

Author(s):  
Mitali Madhusmita Sahoo ◽  
Sangeeta Raut ◽  
Achlesh Davery ◽  
Naresh Kumar Sahoo

Abstract Brominated phenols are listed as priority pollutants, and are the key components of paper pulp wastewater together with nitrophenol and chlorophenol. However, the biodegradation of bromophenol in a mixed substrate system is very scanty. In the present investigation, simultaneous biodegradation kinetics of three substituted phenols (4-bromophenol, 4-BP; 4-nitrophenol, 4-NP; and 4-chlorophenol, 4-CP) were investigated using Arthrobacter chlorophenolicus A6. A 23 full factorial design was applied with varying 4-BP and 4-CP from 75–125 mgl− 1and4-NP from 50–100 mgl− 1. Almost complete degradation of this mixture of substituted phenols was achieved at an initial concentration combination of 125, 125, and 100 mgl− 1of 4-CP, 4-BP, and 4-NP, respectively in 68 h. Statistical analysis of the results revealed that among the three variables, 4-NP had the most prominent influence on both degradations of 4-CP and 4-BP. While the concentration of 4-CP had a strong negative interaction effect on the biodegradation of 4-NP. Irrespective of the concentration levels of these three substrates, 4-NP was preferentially biodegraded over 4-CP and 4-BP. Further, 4-BP biodegradation rates were found to be higher than that of 4-CP followed by 4-NP. Besides, the variation of biomass yield coefficient of the culture was investigated at different initial concentration combinations of these substituted phenols. Although the actinomycetes consumed 4-NP at a faster rate, the biomass yield was very poor. This revealed that the microbial cells were more stressed when grown on 4-NP compared to 4-BP and 4-CP. Overall, this study revealed the prospective of A. chlorophenolicus A6 for the degradation of 4-BP in mixed substrate systems.

2020 ◽  
Vol 10 (1) ◽  
pp. 4939-4943

Biodegradation of p-bromophenol (4-BP) along with p-chlorophenol (4-CP) was investigated in batch shake flasks using a actinomycetes strain of Arthrobacterchlorophenolicus A6. A Two level full factorial design at two different levels (low and high) was applied to perform the biodegradation of 4-CP and 4-BP in the mixed substrate system. Result reveals that the presence of 4-CP in low concentration range in the mixture (20–60 mgl-1) did not inhibit 4-BP biodegradation by the actinomycetes. However, at high concentration range of 4-CP (100-200 mgl-1), the 4-BP biodegradation was inhibited. Further, 4-BP degradation was faster than 4-CP. In order to study variation in the specific degradation rate of these pollutants and their interaction effect exist between them, the experimental data were fitted to a sum kinetics model. The experimental data have been fitted with the model with a high correlation coefficient value (R2> 0.94). The model fitted data reveals a strong negative interaction effect of 4-CP on biodegradation of 4-BP by the A. chlorophenolicusA6.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 155-162 ◽  
Author(s):  
G. Jin ◽  
A. J. Englande

Kinetics of Carbon Tetrachloride biodegradation are evaluated in a continuous-flow fixed-biofilm reactor with controlled initial redox potential. The column was seeded with a mixed culture of indigenous microorganisms Pseudomonas cepacia and Providencia stuartii. The fixed biofilm reactor exhibited 98%–99.9% biodegradation of CT introduced into the reactor at an initial concentration of about 200 μg/l for retention times of 1 to 4 days respectively. Four models were employed to evaluate the kinetics of CT biodegradation. These included: Eckenfelder (1989), Arvin (1991), Bouwer and McCarty (1985) and a biphasic model. Comparison of calculated results with observed results between these models agreed very closely to each other (0.968 < R2 < 0.999). Predicted performance was best described by the model of Bouwer and McCarty (1985). However, the biphasic and Eckenfelder models provided excellent correlations and were much simpler to apply. The biphasic model yielded very good correlations of the data for all detention times evaluated; whereas, the Eckenfelder model effected comparable results only at the longer retention times studied.


1996 ◽  
Vol 34 (5-6) ◽  
pp. 67-74 ◽  
Author(s):  
D. Orhon ◽  
S. Sözen ◽  
N. Artan

For single-sludge denitrification systems, modelling of anoxic reactors currently uses the kinetics of aerobic heterotrophic growth together with a correction factor for anoxic conditions. This coefficient is computed on the basis of respirometric measurements with the assumption that the heterotrophic yield remains the same under aerobic and anoxic coditions. The paper provides the conceptual proof that the yield coefficient is significantly lower for the anoxic growth on the basis of the energetics of the related metabolic processes. This is used for the interpretation of the very high values for the correction factor experimentally determined for a number of industrial wastewaters. A default value for the anoxic heterotrophic yield coefficient is calculated for domestic sewage and compatible wastewaters and proposed for similar evaluations.


1980 ◽  
Vol 45 (9) ◽  
pp. 2391-2399 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval

The polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene with butyllithium as the initiator was investigated by the gas chromatographic method. After completion of the initial period of the reaction, its order with respect to the initial concentration of initiator is negative at the concentrations of the latter between 0.01 and 0.25 mol/l, and positive at higher concentrations. A reaction scheme has been suggested with respect to the "cross" association of butyllithium and of the "living" oligoisoprene.


1980 ◽  
Vol 45 (12) ◽  
pp. 3338-3346
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.


Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 810
Author(s):  
Sabrina Sorlini ◽  
Carlo Collivignarelli ◽  
Marco Carnevale Miino ◽  
Francesca Maria Caccamo ◽  
Maria Cristina Collivignarelli

The hepatotoxin microcystin-LR (MC-LR) represents one of the most toxic cyanotoxins for human health. Considering its harmful effect, the World Health Organization recommended a limit in drinking water (DW) of 1 µg L−1. Due to the ineffectiveness of conventional treatments present in DW treatment plants against MC-LR, advanced oxidation processes (AOPs) are gaining interest due to the high redox potential of the OH• radicals. In this work UV/H2O2 was applied to a real lake water to remove MC-LR. The kinetics of the UV/H2O2 were compared with those of UV and H2O2 showing the following result: UV/H2O2 > UV > H2O2. Within the range of H2O2 tested (0–0.9 mM), the results showed that H2O2 concentration and the removal kinetics followed an increasing quadratic relation. By increasing the initial concentration of H2O2, the consumption of oxidant also increased but, in terms of MC-LR degraded for H2O2 dosed, the removal efficiency decreased. As the initial MC-LR initial concentration increased, the removal kinetics increased up to a limit concentration (80 µg L−1) in which the presence of high amounts of the toxin slowed down the process. Operating with UV fluence lower than 950 mJ cm−2, UV alone minimized the specific energy consumption required. UV/H2O2 (0.3 mM) and UV/H2O2 (0.9 mM) were the most advantageous combination when operating with UV fluence of 950–1400 mJ cm−2 and higher than 1400 mJ cm−2, respectively.


1987 ◽  
Vol 31 (1) ◽  
pp. 119-131 ◽  
Author(s):  
B.S. Gevert ◽  
J-E. Otterstedt ◽  
F.E. Massoth

2005 ◽  
Vol 11 (2) ◽  
pp. 59-62 ◽  
Author(s):  
Dragisa Savic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
Miroslav Vrvic

The batch oxidation kinetics of ferrous iron by Acidithiobacillus ferrooxidans were examined at different oxygen transfer rates and pH in an aerated stirred tank and a bubble column. The microbial growth, oxygen consumption rate and ferrous and ferric iron were monitored during the biooxidation. A kinetic model was established on the basis of the Michaelis-Menten kinetic equation for bacterial growth and the constants estimated from experimental data (maximum specific growth rate 0.069 h-1, saturation constant 2.9 g/dm3, and biomass yield coefficient based on ferrous iron 0.003 gd.w./gFe). Values calculated from the model agreed well with the experimental ones regardless of the bioreactor type and pH conditions.


2011 ◽  
Vol 233-235 ◽  
pp. 567-570
Author(s):  
Juan Qin Xue ◽  
Wei Bo Mao ◽  
Dan Dan Wen ◽  
Jing Xian Li ◽  
Yu Jie Wang

Investigated the sorption kinetics of methylene blue on spherical chitosan resin. Studied the influences of ionic strength, pH, initial concentration on the adsorption process. The adsorption of methylene blue increases with the decreasing ionic strength and the increasing pH and the initial concentration of the system. Furthermore, the adsorption process correspondes with Lagergren pseudo-second kinetic equation and the finess (R2) of the model was above 0.99.


1982 ◽  
Vol 60 (7) ◽  
pp. 848-852 ◽  
Author(s):  
Yoshiro Ogata ◽  
Kazushige Tanaka

The oxidation of diphenyl sulfide (Ph2S) by hydrogen peroxide in the presence of a catalytic amount of sodium metavanadate (NaVO3) has been studied kinetically by means of iodometry of hydrogen peroxide. The reaction rate is expressed as: v = k[NaVO3]st[Ph2S]2, when the concentration of catalyst is very low and [Ph2S]0/[H2O2]0 > 2, where []st and []0 mean stoichiometric and initial concentration, respectively. The effective oxidant may consist of polymeric as well as monomeric peroxyvanadate in view of the effect of concentration of catalyst on the rate. The main oxidizing species at low concentration of catalyst seems to be diperoxyvanadate VO5−. The rate constant k2 in v = k2[Ph2S]2 tends to decrease with initial concentration of H2O2, which is present in excess of the catalyst. A probable mechanism for the oxidation is discussed.


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